Fuctioal Polymers From Reewable Resources S. Shag, A. Ro, S. J. Huag ad R. A. Weiss Polymer Program Uiversity of Coecticut Storrs, CT New Eglad Gree Chemistry Cosortium Aual Meetig Uiversity of Maie ro, ME May 31, 2006
Polymers based o reewable resources crops, grasses, agricultural byproducts Raw materials are sustaiable; Polymers ca be desiged to be biodegradable Moomers From Reewable Resources Lactic Acid H H Fermetatio of agricultural by-products (carbohydrates), e.g., cor starch Itacoic Ahydride Pyrolysis of citric acid, or Fermetatio of carbohydrates to form itacoic acid, followed by dehydratio Stearyl Methacrylate Derived from fatty acid from aimal or vegetable fats or oils
Poly(lactic acid), PLA Azeotropic Distillatio H H - H 2 * * High Molecular Weight PLA Rig peig Polymerizatio (Sct 2 with coiitiator) Codesatio -H 2 H H Depolymerizatio Sct 2 H 3 C Prepolymer M ~ 5000 Lactide Drumwright, R. E.; Gruber, P. R.; Heto, D. E. Adv. Mater. 2000. 12. 1841. Applicatios: Fibers, films, moldable thermoplastics (T m ~ 175 C), sutures Deficiecies: Low T g (~ 60 C), Narrow melt processig widow, Brittle plastic, hydrophobic; icompatible with other polymers (bleds)
Ioomers Predomiatly hydrophobic polymers that cotai modest amouts of boded acid or salt groups (~ 15 mol%) Iterchai associatio of salt groups sigificatly alters thermal properties, mechaical properties ad rheology. PS 1.82 NaSPS 3.44 NaSPS 5.81 NaSPS Applicatios: coatigs, fibers, thermoplastics, adhesio promoters, compatibilizers, viscosifiers, permselective membraes, hydrogels
Research Goals Sythesize ad Characterize Ioomers Derived from Lactic Acid, Itacoic Ahydride ad Stearyl Methacrylate - + Radom Ioomer - + - + - + ITA H 2 C C H 2 C H 2 C H 2 C C CH 2 CH m ITA H 2 C C H 2 C m C (a) x H PLA (b) SM - + Telechelic Ioomer - + - + etate, Sct 2 telechelic PLA B PLA ITA H
Radical copolymerizato of ITA ad SM ITA + SM (CH 2 ) 17 AIBN, 80 o C Ethyl Acetate co(ita/sm) m (CH 2 ) 17 Absorptio 6 + 5 No peak 4 3 2 1 0 AIBN, 80 o C Ethyl 1782 Acetae 1730 1862 (CH 2 ) 17 Copolymer Mixture ITA SM CH 2 C 2.0 1.5 1.0 0.5 0.0 1800 CH 2 1780 1760 m (CH 2 ) 17 Copolymer Mixture 1740 1720 1731 1700 + 1720 1680 1660 (CH 2 ) 17 AIBN, 80 o C Ethyl Acetae CH 2 C 3000 2500 2000 1500 1000 1601 Wavelegth (cm -1 ) IR evidece for copolymerizaito: ü 1862, 1782 cm -1 : ITA (ahydride) 5 member rig ü shift of C= i SM from 1720 to 1731 cm -1 idicatig reactio of C=C ü disappearace of peak at 1601 cm -1 : reactio of C=C
Copolymerizatio of ITA ad SM 1.0 0.8 F1 = r r f + f1 f2 2 f f + r f 2 1 1 2 1 f1 + 1 2 2 2 2 r ITA = r 1 = 0.53 r SM = r 2 = 0.12 F ITA 0.6 0.4 0.2 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Radom Copolymers J. Wallach, PhD Dissertatio, Uiv. Co., 2000 f ITA M (25k 60kDa) decreased with icreasig f ITA
Thermal behavior of ITA-co-SM copolymers Heat Flow (W/g) 10 0-10 DSC: 1 st sca after ppt from sol. Icreasig SM compositio g f e d c b a f ITA 0 0.29 0.40 0.53 M (kda) 57.1 45.1 33.0 34.8 T m ( C) 30.2 31.2 32.1 44.7 DH (J/g SM) 62.8 83.0 77.0 87.9-20 0.54 0.45 29.1 24.1 48.2 45.6 50.9 21.3-40 -20 0 20 40 60 80 100 120 Temperature ( o C) Crystalliity is due to the SM side chai packig Meltig temperature icreased with icreasig ITA cotet! Effect of ITA o crystalliity was complicated. No glass trasitio was observed (T g(ita) ~ 130 C).
Crystallie structure of ITA-co-SM Itesity SAXS (100 % ITA) (45) (53.8) (52.8) (29.0) (0) 0.5 1.0 1.5 2.0 2.5 3.0 q (m -1 ) Compositio (mol% ITA) 0 29.0 45 52.8 53.8 100 d (m) 2.95 2.96 3.98 3.18 3.55 Legth of alkyl side chai = 2.5 m -- WAXD (58% ITA) Itesity (45) (53) (45) (29) Poly(SM) 0.417 m characteristic of -alkyl hexagoal packig, 10 12 14 16 18 20 q (m -1 )
Side-Chai, Stearyl Methacrylate Crystals L L L Itercalated Crystal Bilayer Crystal 3.9 m 27 Z-Stearate Bilayer Crystal
ITA-co-SM Ioomers (M =33 kda; 40 mol% ITA) 1630 Ca 2+ Salt (50%) 1570 1570 Na + Salt (100%) ITA-co-SM (40% ITA) 2000 1900 1800 1700 1600 1500 1400 Waveumber (cm -1 ) IR evidece of eutralizatio Peak ~ 1550-1650 cm -1 due to C -
Ioomer Structure ad Properties Itesity SAXS Na-salt (100%) Ca-salt (50%) ITA-co-SM (40% ITA) Probe Height 1.0 0.8 0.6 0.4 0.2 ITA-co-SM (40% ITA) TMA (F = 60 mn) Ca-Salt (50%) Na-Salt (100%) Poly(SM) 0.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 q (m -1 ) 0 20 40 60 80 Temperature ( o C) Ioic aggregatio was observed Log spacig of SM crystals icreased upo eutralizatio Neutralizatio icreased the elasticity of the polymer.
Chemical Recyclig of PLA by Trasesterificatio Trasesterificatio v Ucatalyzed - slow process, reactio temperature 250-300 C. v Catalyzed - lower time ad temperature (J. Wallach, PhD Dissertatio, Uiv. Co., 2000). Sct 2. FDA approved. Mechaism H H R H S ct 2 H R Sct 2 H + R H Sct 2
Sythesis of ω -carboxylate fuctioalized PLA A. Sythesis of methacrylate-termiated PLA H + H Sct 2 H 2-hydroxyethyl methacrylate poly(lactic acid) telechelic PLA A H B. Fuctioalizatio with itacoic ahydride Telechelic PLA A H + itacoic ahydride ethyl acetate, 120 o C, Sct 2 telechelic PLA B H
H C= stretch C--H i-plae bed ad C- stretch Broad H stretch Carboxylic C= stretch C=C stretch
M Asymmetric carboxylate aio stretch
1 H-NMR Spectrum of Fuctioalized PLA ligomer d Ed group Aalysis - M = 1930, with 25 LLA uits c d h c h
Glass Trasitio Temperatures of PLA-ITA Telechelic Ioomers Catios = Li +, Na +, K +, Ca 2+, Z 2+, Y 3+ 55 50 c = 0.6 mol% (M ~ 13,000 g/mole) T g ( o C) 45 40 35 c = 2.1 mol% M ~ 3,000 g/mole 30 K Na Li Ca Z Y 25 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 q/a For higher molecular weight (M ~ 15,000 900,000), T g was relatively isesitive to fuctioalizatio
Ackowledgmets Fudig by: New Eglad Gree Chemistry Cosortium NSF/EPA
Petroleum-Based Polymers * Hydrophobic ad resistat to biodegradatio Escalatig prices of petroleum (oly ~ 2% of petroleum is used for polymers) * Muicipal Solid Waste Geeratio, Recyclig, ad Disposal i the Uited States: Facts ad Figures for 2003, U.S. Evirometal Protectio Agecy, 2003. Tullo, Chem. Eg. News. 2005, 83, 19.
Evirometal Cocers Plastics productio has early doubled every 10 years for four decades. Evirometal Issue Sustaiability Issue Plastic are the largest volume compoet i U.S. ladfills (~ 25%) Existig petroleum resources are limited.
Biodegradable Polymers Aliphatic Polyesters from Hydroxyacids Poly(3-hydroxybutyric acid) Poly(lactic acid) NatureWorks LLC
Itacoic Ahydride Ramos PEG fuctioalizatio d + d - A R H d + RH Sct 2 B d - Biocompatible citric acid distillatio, fermetatio of carbohydrates (Aspergillus terreus) R H Ramos, M. Multi-compoet Hydrophilic-Hydrophobic Systems From Itacoic Ahydride. Ph.D. Thesis, Uiversity of Coecticut, Storrs, CT, 2002.